Supernatural: Sam and Dean (Jared Padalecki, Jensen Ackles) investigate the eerie case of a ballerina who literally danced herself to death (9 p.m. KTLA).Fairly Legal: In the second season, the feisty mediator (Sarah Shahi) has a new conflict — and a potential romance — on her hands in the form of a sharp attorney (Ryan Johnson). Virginia Williams and Michael Trucco also star (9 p.m. USA).Bering Sea Gold: This unscripted dangerous profession season ends its season (10 p.m. Discovery).Spartacus: Vengeance: The capture of a prominent Roman gives Spartacus (Liam McIntyre) a chance to get revenge in this new episode of the historical action series (10 p.m. Starz).In Plain Sight: The series enters its fifth and final season tackling a series of storylines building up to its finale. Mary McCormack and Frederick Weller star (10 p.m. USA).